Unittests: Account for b979fe19e5 (fix one test and add two more)

- Unused XML namespace declarations *are supposed* to be removed
- XML namespace declarations that are used as prefix for elements/attributes *must not* be removed

unittests/xml-well-formed.svg

@@ -1,9 +1,11 @@
 <?xml version="1.0" encoding="UTF-8" standalone="no"?>
-<svg xmlns="http://www.w3.org/2000/svg" xmlns:foo="http://foo/">
+<svg xmlns="http://www.w3.org/2000/svg" xmlns:foo="http://foo/" xmlns:bar="http://bar/" xmlns:baz="http://baz/">
 	<!-- &lt;Jack &amp; Jill&gt; -->
 	<title>2 &lt; 5</title>
 	<desc>Peanut Butter &amp; Jelly</desc>
 	<glyph id="lt" unicode="&lt;"/>
 	<glyph id="amp" unicode="&amp;"/>
+	<glyph id="gt" unicode="&gt;" bar:attr="xyz"/>
+	<baz:glyph id="quot" unicode="&quot;"/>
 	<text x="50" y="50">&#x389;TML &#x26; CSS</text>
 </svg>